”Chicken Run” scratched out a milestone this weekend: The animated feature’s North American gross crossed the $100 million threshold in its ninth week of release. The prison break comedy became the third Dreamworks SKG release (after ”Gladiator” and ”What Lies Beneath”) and only the 11th film this year to join that select big money club.

But diehard animation fans are still clucking over what — or rather who — is missing from this feathered farce. Though ”Chicken Run”’s codirectors, Nick Park and Peter Lord, are newcomers to feature length films, they are already audience and critical favorites. Lord, who cofounded England’s famed Aardman Animations, has earned two Academy Award nominations for directing two short animated films, while Park’s Aardman produced shorts have won three Oscars. Yet Park’s most famous creations, the cheese obsessed inventor Wallace and his exasperated dog Gromit, don’t have so much as a cameo in ”Chicken Run.” Instead, the film — which is Aardman’s first joint venture with an American studio — features all new characters, including Rocky the Rooster (voiced by Mel Gibson), heroic hen Ginger (Julie Sawalha of ”Absolutely Fabulous”), and an evil piemaker (Miranda Richardson).

According to Park, ”Wallace and Gromit: The Motion Picture” would have been ”an obvious choice — there was a lot of demand for it.” In fact, a movie with the well known duo would have been a shoo-in for both commercial and critical success. Aardman earns an estimated $1.6 million in licensing fees each year, much of it from Wallace and Gromit merchandise, and the short films ”The Wrong Trousers” (1996) and ”A Close Shave” (1995) — which both featured Wallace and Gromit — won Oscars. (The first W&G entry, 1992’s ”A Grand Day Out” was nominated, too — but lost to another Park featurette, ”Creature Comforts”).

Even so, Park and Lord chickened out — which had more to do with their partnership than with profits. Park chose to share directing duties with his longtime producer Lord and wanted to give his partner equal say in the creative process — a difficult endeavor with characters as established as Wallace and Gromit. ”We thought, Let’s just start with a clean slate,” says Park, 42. ”I wanted both of us to be invested in the story, so it needed to be something we thought up together.” Devoted fans, however, will find a sly reference to Wallace and Gromit in an early scene of ”Chicken Run.” The name Feathers McGraw (the criminal penguin from the short film ”The Wrong Trousers”) is scrawled on the wall of the coal bin where Ginger is held in solitary confinement.

Though Wallace and Gromit are likely to make their way to the big screen, fans will have to be patient. Aardman recently signed a five picture deal with Dreamworks SKG, including a follow-up to ”Chicken Run” based on the fable ”The Tortoise and the Hare.” The labor intensive stop motion animation shoot will take at least two years to complete, meaning that a W&G feature couldn’t arrive in theaters before 2004. As the chickens would say, ”Oh, codswallop!”